Re-enterable splice enclosure
A re-enterable enclosure for a splice between cables, comprises two cover members with internal walls that are configured to form a cavity for enclosing the cable splice when the cover members are engaged with each other in a closed position. At least one of the cover members also has internal walls that are configured to define containment spaces which at least partly surround the cavity. In use, those containment spaces may contain sealant material. At least one internal wall in one cover member can telescope into a containment space in the other cover member so that, if sealant material is contained therein, it will be compressed when the cover members are engaged with each other in the closed position. By changing the containment spaces that are used to contain sealant material, different levels of protection against humidity can be provided for the cable splice in the cavity.
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The present invention is related to U.S. patent application Ser. No. 10/770,095, titled MICROSPHERE-FILLED SEALANT MATERIALS, filed even date herewith.
FIELDThe present invention relates to an enclosure for a splice between cables, the enclosure being of the type that can be re-opened, re-enterable, to permit access to the cable splice when required and, preferably, then re-sealed. The cable may, for example, be a telecommunications cable, a power cable or an optical fibre cable.
The cable splice may, for example, be a longitudinally-extending splice (i.e. a splice between cables that extend generally from opposite directions) or a so-called “pig-tail”, or butt, splice (i.e. a splice between cables that extend generally from the same direction).
BACKGROUNDA cable splice will generally require protection from the effects of the environment in which it is located and, more especially, will require protection against mechanical impact and the entry of moisture. Protection of the cables against strain will often also be required. Many different enclosures providing different levels of protection for cable splices are already available, including so-called re-enterable enclosures that can be re-opened to permit access to the splice whenever required.
Known re-enterable splice enclosures often take the form of a two-part re-openable housing that defines a cavity around the splice and contains a sealant material. The housing provides protection for the splice against mechanical impact and, in combination with the sealant material, protects the cavity to a required level against the entry of moisture while permitting access to the splice when the housing is re-opened. In some cases, the cavity is completely filled with sealant material (see, for example, the splice enclosures described in U.S. Pat. No. 6,169,250 and, in other cases, the sealant material is pre-formed by molding to particular shapes for use in cable bushings that are located at the ends of the housing (see, for example, the splice enclosures described in WO 02/063736).
SUMMARYThe present invention is concerned with providing a re-enterable splice enclosure that is capable of providing adequate protection for a cable splice against mechanical impact and the entry of moisture without requiring the cavity surrounding the splice to be filled with any suitable sealant material, and without requiring the sealant material to be pre-formed to comparatively complex shapes for use in cable bushings. The invention is, accordingly, also concerned with providing a re-enterable splice enclosure that is capable of providing adequate protection for a cable splice against mechanical impact and the entry of moisture while using a comparatively small amount of sealant material and while being comparatively simple to assemble.
The present invention provides a re-enterable enclosure for a splice between cables, the enclosure comprising two cover members with internal walls that are configured to form a cavity for enclosing the cable splice when the cover members are engaged with each other in a closed position, wherein:
-
- (i) at least one of the cover members has internal walls that are configured to define containment spaces, suitable for containing sealant material, that at least partly surround the cavity, and
- (ii) at least one internal wall in one cover member can telescope into a containment space in the other cover member, thereby to compress any sealant material contained therein, when the cover members are engaged with each other in the closed position.
Advantageously, at least one of the cover members comprises strain-relief members associated with cable entry paths into the cavity. The enclosure is then capable of providing the splice with protection against the effects of cable strain in addition to that provided, by the cover members, against mechanical impact and that provided, by the cover members in combination with any sealant material in the containment spaces, against the entry of moisture.
By way of example only, splice enclosures in accordance with the invention will be described with reference to the accompanying drawings in which:
The cover members 1, 3 both include internal walls (described in greater detail below) that define central cavity regions 7, 9 respectively. When the cover members 1, 3 are folded together about the hinge 5 and brought into engagement with each other to close the splice enclosure, the cavity regions 7, 9 together form a central enclosed cavity for containing the cable splice that is to be protected. To hold the cover members 1, 3 together in the closed position, latching tabs 11 project upwards from inside the outer longitudinal edge 10 of the upper cover member 1 so that they will slide into a latching space 10A behind the outer longitudinal edge 10 of the lower cover member 3 and engage in respective recesses 12. In addition, to reduce the possibility of any relative movement between the cover members 1, 3 once they are in the closed position, the lower cover member 3 is provided with pins 13 that engage in apertures 14 in the upper cover member 1. In that way, the stress placed on the hinge 5 when the splice enclosure is in use is limited and the risk that the latching tabs 11 will inadvertently disengage from the openings 12 is minimized.
The cavity region 7 in the upper cover member 1 is defined between side walls 15 and double end walls 17 that stand up from the internal surface of the cover member. The side walls 15 are located slightly inside the inner and outer longitudinal edges 2, 10 of the cover member, and extend parallel thereto. The double end walls 17 extend between the ends of the side walls 15 and are arranged at a distance from the respective ends 19 of the cover member 1, thereby creating a space 20 at each end of the upper cover member: each of those spaces 20 is intended, when the splice enclosure is in use, to accommodate a respective upstanding cable strain-relief structure 21 formed at the corresponding end of the lower cover member 3. The strain-relief structures 21 will be described below. The space 17A between the two walls of each double end wall 17 provides a containment space for sealant material, also described below.
The cavity region 9 in the lower cover member 3 is defined between side walls 22 and end walls 23 that stand up from the internal surface of the cover member. The side walls 22 are located slightly inside the inner longitudinal edge 2 of the cover member and the inner wall 10B of the latching space 10A, and extend parallel thereto. The end walls 23 extend between the ends of the side walls 22 and each is arranged at a distance from the respective strain-relief structure 21. The spaces that are thus formed around the cavity region 9, on the outside of the side and end walls 22, 23, provide containment spaces for sealant material as will be described below.
The side walls 15 and the double end wall 17 of the cavity region 7 in the upper cover member 1 stand up above the level of the outer edge of the cover member and are positioned so that, when the cover members 1, 3 are folded together into the closed position, the walls 15, 17 will telescope into the containment space around the cavity region 9 in the lower cover member 3.
The cable entry paths into the splice enclosure are further defined by semi-circular recesses 25B in the end walls of the cover member 1 and the end wall 17 of the cavity region 7.
Referring now to
The splice enclosure comprising the cover members 1, 3 can be used without the addition of any sealant material (i.e. in the form shown in
Referring to
The cable splice is then prepared and the cables are placed on the lower cover member 3 as described above and as illustrated in
The sealant material 27 for the enclosure of
Referring to
As described above, the sealant material 27, 29 for the enclosure of
A particular advantage of the splice enclosures comprising cover members 1, 3 as described above is that one type of enclosure can be used to provide several levels of protection against humidity simply by the inclusion of sealant material at appropriate locations within the cover members. Indeed, the splice enclosure illustrated in
The splice enclosures are of simple construction, and use comparatively few components so that they are easy to assemble in the field, even at difficult or inaccessible locations.
The modification required to change the level of protection (i.e. the addition of sealant material) can be easily carried out by the manufacturer or installer, particularly when a liquid sealant material is used because there is then no need to stock pieces of gel that are preformed to a particular shape. The maximum amount of sealant material (
Because only one sealant material is used in the splice enclosures shown in
Preferably, the sealant material 27, 29 has sufficient long-term resilience to ensure, once it has been compressed by closing the cover members 1, 3, that effective sealing is maintained until the splice enclosure is re-opened. Advantageously, the sealant material permits the splice enclosure then to be re-sealed (and, if required, opened and re-sealed again several times) and to continue to provide the same level of protection for the cable splice. A suitable sealant material is described in our co-pending patent application Ser. No. 10/770,095 of even date entitled “MICROSPHERE-FILLED SEALANT MATERIALS”, and which is incorporated herein by reference. If required, however, one or more external resilient members can be positioned in known manner at suitable locations in the cover members 1, 3 to apply the required compressive force to the sealant material when the splice enclosure is closed.
It will be appreciated that various modifications could be made to the construction of the cover members 1, 3 without affecting the protective function of the splice enclosure. In one modification, the single hinge 5 between the two cover members 1, 3 is replaced by two hinges 5A, 5B as illustrated in
The provision of the strain-relief structures 21 in the splice enclosure, although convenient, will limit the size of cable with which the splice enclosure can be used. For use with larger-diameter cables, the strain-relief structures 21 can be omitted and conventional cable ties used instead. Alternatively, the strain-relief structures 21 can be designed to accommodate the largest-diameter cables with which the splice enclosure is intended to be used, and some additional mechanism can be provided to enable the enclosure to be used with smaller-diameter cables.
With the benefit of the teachings of this patent, one of skill in the art could apply the present invention to any size cable or any desired pair count.
In the splice enclosure shown in
It will further be appreciated that a splice enclosure of the same general type as those illustrated in the drawings could be used to protect a so-called “pig tail”, or butt, splice (i.e. a splice between cables that extend generally from the same direction, rather than from opposite directions as shown in
Further modification of the cable entry paths of any of the splice enclosures described above with reference to the drawings would enable protection to be provided for splices between different numbers of cables, for example a longitudinal splice between one cable extending from one direction and two cables extending from the other direction.
Claims
1. A re-enterable enclosure for a splice between cables, the enclosure comprising:
- first and second cover members releasably engageable with each other, wherein the cover members are joined to each other by at least one hinge, the first and second cover members being configured to form a cavity for enclosing the cable splice when the cover members are engaged with each other in a closed position, wherein the cavity for enclosing the cable splice is essentially free of sealant material, and including: (i) a plurality of internal walls in the first cover member configured to define a first containment space for containing sealant material, wherein the first containment space at least partly surrounds the cavity, and (ii) a plurality of internal walls in the second cover member, at least one of the plurality of internal walls configured to telescope into the first containment space in the first cover member when the cover members are engaged with each other in the closed position.
2. A splice enclosure as claimed in claim 1, further comprising a cable entry path into the cavity, and wherein said cable entry path traverses the first containment space.
3. A splice enclosure as claimed in claim 2, wherein the plurality of internal walls in the second cover member define a second containment space for containing sealant material.
4. A splice enclosure as claimed in claim 2, wherein at least one of the first and second cover members further comprises strain-relief members associated with said cable entry path.
5. A splice enclosure as claimed in claim 1, wherein the plurality of internal walls in the second cover member define a second containment space for containing sealant material, wherein the first and second containment spaces are configured such that the containment space in one of the first and second cover members can telescope into the containment space in the other one of the first and second cover members when the first and second cover members are engaged with each other in the closed position.
6. A splice enclosure as claimed in claim 5, further comprising a sealant material contained in the first and second containment spaces.
7. A splice enclosure as claimed in claim 6, wherein the first and second containment spaces all contain the same sealant material.
8. A splice enclosure as claimed in claim 1, further comprising a sealant material contained in the first containment space.
9. A splice enclosure as claimed in claim 8, wherein the first containment space contains a sealant material that has been poured into the first containment space and then cured.
10. A splice enclosure as claimed in claim 1, wherein the splice cavity is of elongate form, and the splice enclosure further comprises first and second cable entry paths into the cavity from opposed ends thereof.
11. A splice enclosure as claimed in claim 10, wherein the plurality of internal walls in at least one of the first and second cover members are configured to define transverse containment spaces at said opposed ends of the cavity, said transverse containment spaces oriented transverse to the elongate splice cavity.
12. A splice enclosure as claimed in claim 11, wherein the cable entry paths traverse said transverse containment spaces.
13. A splice enclosure as claimed in claim 12, wherein the transverse containment spaces are defined by the plurality of internal walls in both the first and second cover members.
14. A splice enclosure as claimed in claim 13, wherein the plurality of internal walls defining transverse containment spaces in one of the first and second cover members can telescope into transverse containment spaces in the other one of the first and second cover member when the cover members are engaged with each other in the closed position.
15. A splice enclosure as claimed in claim 11, wherein the plurality of internal walls in one of the first and second cover members are configured to provide longitudinal containment spaces that extend along both sides of the cavity between the opposed ends thereof.
16. A splice enclosure as claimed in claim 15, wherein the plurality of internal walls in the other one of the first and second cover members can telescope into the longitudinal containment spaces when the cover members are engaged with each other in the closed position.
17. A splice enclosure as claimed in claim 15, wherein none of the containment spaces are essentially free of sealant material.
18. A splice enclosure as claimed in claim 15, wherein the transverse containment spaces contain sealant material.
19. A splice enclosure as claimed in claim 18, wherein the longitudinal containment spaces contain sealant material.
20. A splice enclosure as claimed in claim 1, wherein the cover members are molded components.
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- A copy of the Search Report for International Application No. PCT/US2005/000106, mailed on Jun. 16, 2005 (7 pages).
Type: Grant
Filed: Feb 2, 2004
Date of Patent: Nov 28, 2006
Patent Publication Number: 20050167147
Assignee: 3M Innovative Properties Company (St. Paul, MN)
Inventors: Yvonnick Marsac (Drefféac), Christophe Desard (Herbignac)
Primary Examiner: Chau N. Nguyen
Attorney: John A. Burtis
Application Number: 10/770,377